As families around the world mourn those lost in the Malaysia Airlines Flight MH17 disaster, a group dedicated to saving lives mourns its own: At least six public health AIDS researchers and advocates died in the flight shot down over Ukraine on July 17.

In the community of professionals working to fight HIV/AIDS, the most well-known of the lost was pioneering researcher Dr. Joep Lange. But colleagues and partners honored and mourned the loss of all six dedicated public health professionals, who each made important contributions in the fight against the AIDS pandemic.

Those lost include Dutch activists Lucie van Mens, who championed the female condom; Martine de Schutter, who worked on behalf of marginalized HIV patients; and Pim de Kuijer, who lobbied for increased funding. World Health Organization spokesman Glenn Thomas was also on the flight, as was Lange's partner, Jacqueline van Tongeren, who worked as an AIDS public health advocate. [30 Years Later: AIDS by the Numbers]

Conference attendees marked the losses throughout the event.

"This meeting has been extremely intense, with overwhelming support from so many international colleagues who personally knew them, and so many people who have worked with them," Ton Coenen, director of AIDS Fonds, which worked with both Schutter and Kuijer, told Live Science in an email interview. "There is a very strong sense of persistence to keep up our fight in their spirit."

Here's how the crash victims contributed to the global fight against HIV and AIDS:

Lucie van Mens

Van Mens worked with The Female Health Company (FHC) and other organizations to improve access to the underutilized female condom, which protects women protect against contracting HIV during sex. She led the development of female condom programs in seven African countries, working with local groups to ensure the efforts were sensitive to local preferences, the FHC said in a memorial.

"Lucie was persistent in her quest to improve the sexual health of women and their families worldwide," the agency said.

Before joining the FHC, Van Mens coordinated the international partnership Universal Access to Female Condoms (UAFC) and had served in various Dutch HIV/AIDS organizations since 1995. In a memorial, the UAFC noted Van Mens' "passion for increasing access to female condoms" and "relentless efforts and energy to push the case of female condoms forward."

Van Mens' work on the female condom was "highly crucial, because [the female condom] doesn't get much attention," Coenen said. The little-known female condom has proven popular among both women and men in studies by the FHC and others. The condoms give women greater control over decisions regarding their sexual health, FHC noted.

Martine de Schutter and Pim de Kuijer

De Schutter and de Kuijer both served in the Dutch organizations Stop AIDS Now! and AIDS Fonds.

De Schutter worked on behalf of marginalized groups, including sex workers; lesbian, gay, bisexual and transgender people; and those who use injectable drugs. Members of these groups face 10 to 20 times the risk of HIV infection, but only 8 percent of them have access to HIV services, according to Stop AIDS Now!.

Before joining Stop AIDS Now! this year, de Schutter served as executive coordinator at AIDS Action Europe, where she helped keep AIDS on the European political agenda, the organization said in a memorial. Under her leadership, AIDS Action Europe grew into a network of more than 400 members.

In all her work, de Schutter showed a commitment to excluded populations, the agency said. "Martine could not stand injustice and fought for equality for all groups in society," the agency said. "We have lost a monumental contributor to the fight against HIV."

Colleagues praised de Kuijer's straightforward manner, noting that he preferred to put "lobbyist" on his business cards, instead of the euphemistic "policy adviser."

In that capacity for Stop AIDS Now!, de Kuijer helped convince the Dutch government to reverse a 12-million-euro cut to AIDS program funding, and helped to prevent the passing of a bill that would have required mandatory registration of sex workers.

Pim de Kuijer, who died in the crash of Malaysia Airlines Flight MH17, fought for funding to benefit people with HIV.Credit: Aids Fonds

He brought both persistence and charm to his position, the agency said in a memorial. "He was a diplomat, graciously approaching people from all cultural backgrounds and at all levels," the agency said.

"Our colleagues were inspiring and beautiful people who we will forever embrace in our hearts," Coenen said.

Joep Lange and Jacqueline van Tongeren

Lange, whom Coenen called "crucial in the fight against HIV," served as president of the International AIDS Society from 2002 to 2004, among several other high-level positions. He had studied HIV and its treatments since 1983, shortly after the virus's discovery.

Lange founded the PharmAccess Foundation and the Health Insurance Fund, which aim to bring HIV treatment to poor populations in Africa, as well as the Amsterdam Institute for Global Health and Development (AIGHD), which called him "one of the key global figures in AIDS research" in a memorial.

Lange was an early and energetic proponent of the combination treatments that have helped keep viral loads low enough to prolong life for people with HIV. He also pioneered research into methods of preventing mother-to-child transmission of HIV, and made early pushes for global access to HIV treatment.

"Millions around the world, especially in Africa, are now alive because of the contribution that he made," said Professor Peter Mugyenyi, a Ugandan researcher, in an AIGHD memorial to Lange. "We shall miss this gentle, humanitarian person, and a great scientist of our time."

Lange's partner, Jacqueline van Tongeren, was also aboard the plane bound for the conference. Van Tongeren began her career in health care as a nurse, caring for HIV and AIDS patients. With her firsthand medical experience, van Tongeren was "right at home in the field" as she set up many communications initiatives at AIGHD, eventually becoming its director of communications, the agency said.

"She was a passionate HIV advocate, devoted to strengthening human resources for health and improving the health workforce," the IAS said in a memorial.

Glenn Thomas

Thomas had worked at WHO for more than a decade before he died aboard Flight MH17, the organization said in a statement. Since 2012, Thomas had worked in the media team at WHO's Department of Communications, coordinating with journalists to share information on WHO's health efforts with the public. Before that, he worked with the BBC.

"Glenn will be remembered for his ready laugh and his passion for public health," WHO said. The agency quoted Thomas' sister as saying he "died doing what he loved."

Since the HIV epidemic began, WHO has coordinated global public health responses. The agency works with UNICEF to prevent mother-to-child prevention of HIV, supports member countries in their efforts to combat the pandemic and leads several other HIV-related efforts.